merge: Block H - Agent platform kernel (tools/steps/blocks/tabs plugin-contributable)

app/ai/action_mapper.py

@@ -6,9 +6,12 @@ Supports keyword-based intent detection for common CRM operations.
 
 from __future__ import annotations
 
+import logging
 import re
 from typing import Any
 
+logger = logging.getLogger(__name__)
+
 # Precompiled patterns for intent detection
 _PATTERNS = {
     "create_contact": re.compile(
@@ -27,6 +30,37 @@ _PATTERNS = {
     "help": re.compile(r"\b(help|what can you do|assist)\b", re.IGNORECASE),
 }
 
+# Plugin-contributed intents: pattern -> callable(query, context) -> list[dict] | None.
+# Registered via ``register_intent_pattern`` so plugins can extend the fallback
+# mapper without touching core code (Block H / HC-A).
+_CONTRIBUTED_INTENTS: list[tuple[re.Pattern[str], Any]] = []
+
+
+def register_intent_pattern(
+    pattern: str | re.Pattern[str],
+    handler: Any,
+    *,
+    owner: str = "",
+) -> None:
+    """Register a plugin-contributed intent for the fallback action mapper.
+
+    Args:
+        pattern: Regex (compiled or raw string) matching the user query.
+        handler: Callable ``(query, context) -> list[dict] | None`` producing
+            proposed actions when the pattern matches.
+        owner: Optional plugin name, used by ``unregister_intent_patterns``.
+    """
+    compiled = re.compile(pattern) if isinstance(pattern, str) else pattern
+    _CONTRIBUTED_INTENTS.append((compiled, handler))
+
+
+def unregister_intent_patterns(owner: str) -> None:
+    """Remove all intents contributed by ``owner`` (plugin deactivation)."""
+    global _CONTRIBUTED_INTENTS
+    _CONTRIBUTED_INTENTS = [
+        entry for entry in _CONTRIBUTED_INTENTS if getattr(entry[1], "owner_tag", None) != owner
+    ]
+
 # Name extraction patterns - using single-quoted strings to avoid escaping issues
 _NAME_PATTERNS = [
     re.compile(r"\b(?:named|called|for)\s+['\"]?([^'\".,]+)['\"]?", re.IGNORECASE),
@@ -147,6 +181,16 @@ def map_query_to_actions(query: str, context: dict[str, Any] | None = None) -> l
             }
         )
 
+    # --- Plugin-contributed intents (Block H / HC-A) ---
+    for pattern, handler in _CONTRIBUTED_INTENTS:
+        try:
+            if pattern.search(q):
+                contributed = handler(query, context)
+                if contributed:
+                    actions.extend(contributed)
+        except Exception:
+            logger.warning("Contributed intent handler failed", exc_info=True)
+
     # --- Generic fallback ---
     if not actions:
         if _PATTERNS["help"].search(q):

app/ai/agent_loop.py

@@ -50,7 +50,7 @@ if TYPE_CHECKING:
 
     from sqlalchemy.ext.asyncio import AsyncSession
 
-    from app.plugins.builtins.ai_assistant.tool_registry import ToolRegistry
+    from app.ai.tool_registry import ToolRegistry
 
 logger = logging.getLogger(__name__)
 
@@ -394,27 +394,21 @@ async def run_react_loop(
                     if agent_run_id:
                         try:
                             from app.plugins.builtins.contracts import get_contract_registry
-                            from app.plugins.builtins.kommunikation.models import CommConversation
-                            from sqlalchemy import select as sa_select
                             komm = get_contract_registry().get("kommunikation")
                             if komm:
                                 agent_id = getattr(agent_definition, "id", uuid.uuid4())
                                 room_title = f"Agent: {getattr(agent_definition, 'name', 'Agent')}"
-                                existing = await db.execute(
-                                    sa_select(CommConversation).where(
-                                        CommConversation.tenant_id == tenant_id,
-                                        CommConversation.title == room_title,
-                                        CommConversation.is_locked.is_(True),
-                                        CommConversation.locked_by == "automation",
-                                        CommConversation.deleted_at.is_(None),
-                                    )
+                                conv_id = await komm.find_locked_room_id(
+                                    db=db,
+                                    tenant_id=tenant_id,
+                                    plugin_name="automation",
+                                    title=room_title,
                                 )
-                                conv = existing.scalar_one_or_none()
-                                if conv:
+                                if conv_id:
                                     await komm.send_message(
                                         db=db,
                                         tenant_id=tenant_id,
-                                        conversation_id=conv.id,
+                                        conversation_id=conv_id,
                                         sender_id=agent_id,
                                         sender_type="agent",
                                         content=f"Approval required for tool '{tool_name}'",

app/ai/agent_permissions.py

@@ -61,7 +61,7 @@ def _resolve_effective_tool_ids(
     orchestrate tools but never grant additional permissions.
     """
     from app.ai.skill_registry import get_skill_registry
-    from app.plugins.builtins.ai_assistant.contracts import get_tool_registry
+    from app.ai.tool_registry import get_tool_registry
 
     agent_tool_ids: list[str] = list(getattr(agent_definition, "tool_ids", None) or [])
     agent_skill_ids: list[str] = list(getattr(agent_definition, "skill_ids", None) or [])

app/ai/context_builder.py

@@ -221,7 +221,7 @@ async def build_agent_context(
     tool_descriptions: list[dict[str, str]] = []
     tool_ids = list(getattr(agent_definition, "tool_ids", None) or [])
     try:
-        from app.plugins.builtins.ai_assistant.contracts import get_tool_registry
+        from app.ai.tool_registry import get_tool_registry
 
         registry = get_tool_registry()
         if tool_ids:

app/ai/integration_tools.py

@@ -1,170 +0,0 @@
-"""Integration tools — Agent → Workflow + Agent → Knowledge.
-
-Registers AI tools that allow agents to start workflows and ask knowledge questions.
-Builds on: workflow_service, knowledge services, tool_registry.
-"""
-from __future__ import annotations
-import logging
-import uuid
-from typing import Any
-
-logger = logging.getLogger(__name__)
-
-
-def register_integration_tools() -> None:
-    """Register workflow + knowledge tools in the AI tool registry."""
-    from app.plugins.builtins.ai_assistant.tool_registry import get_tool_registry
-    registry = get_tool_registry()
-
-    # ── I-AW: Agent → Workflow ──
-    async def _start_workflow_handler(arguments: dict[str, Any], context: dict[str, Any]) -> dict[str, Any]:
-        """Start a workflow by ID."""
-        from app.services.workflow_service import create_instance
-        from app.core.db import get_worker_session_factory
-        workflow_id = arguments.get("workflow_id", "")
-        tenant_id = context.get("tenant_id")
-        user_id = context.get("user_id")
-        if not workflow_id or not tenant_id:
-            return {"error": "workflow_id and tenant_id required"}
-        factory = get_worker_session_factory()
-        async with factory() as db:
-            instance = await create_instance(
-                db=db,
-                tenant_id=uuid.UUID(str(tenant_id)),
-                workflow_id=uuid.UUID(workflow_id),
-                initiated_by=uuid.UUID(str(user_id)) if user_id else None,
-            )
-            await db.commit()
-            return {"instance_id": str(instance.get("id", "")), "status": instance.get("status", "created")}
-
-    registry.register(
-        name="start_workflow",
-        description="Start a workflow by its ID. Returns the instance ID and status.",
-        parameters={
-            "type": "object",
-            "properties": {
-                "workflow_id": {"type": "string", "description": "UUID of the workflow to start"},
-            },
-            "required": ["workflow_id"],
-        },
-        handler=_start_workflow_handler,
-        plugin_name="integration",
-        required_permission="workflows:read",
-        category="workflow",
-    )
-
-    async def _check_workflow_status_handler(arguments: dict[str, Any], context: dict[str, Any]) -> dict[str, Any]:
-        """Check the status of a workflow instance."""
-        from sqlalchemy import select
-        from app.models.workflow import WorkflowInstance
-        from app.core.db import get_worker_session_factory
-        instance_id = arguments.get("instance_id", "")
-        tenant_id = context.get("tenant_id")
-        if not instance_id or not tenant_id:
-            return {"error": "instance_id and tenant_id required"}
-        factory = get_worker_session_factory()
-        async with factory() as db:
-            result = await db.execute(
-                select(WorkflowInstance).where(
-                    WorkflowInstance.id == uuid.UUID(instance_id),
-                    WorkflowInstance.tenant_id == uuid.UUID(str(tenant_id)),
-                )
-            )
-            inst = result.scalar_one_or_none()
-            if not inst:
-                return {"error": "Instance not found"}
-            return {
-                "instance_id": str(inst.id),
-                "status": inst.status,
-                "current_step": inst.current_step_index,
-                "completed_at": inst.completed_at.isoformat() if inst.completed_at else None,
-            }
-
-    registry.register(
-        name="check_workflow_status",
-        description="Check the status of a workflow instance by its ID.",
-        parameters={
-            "type": "object",
-            "properties": {
-                "instance_id": {"type": "string", "description": "UUID of the workflow instance"},
-            },
-            "required": ["instance_id"],
-        },
-        handler=_check_workflow_status_handler,
-        plugin_name="integration",
-        required_permission="workflows:read",
-        category="workflow",
-    )
-
-    # ── I-AK: Agent → Knowledge ──
-    async def _ask_knowledge_handler(arguments: dict[str, Any], context: dict[str, Any]) -> dict[str, Any]:
-        """Ask a knowledge question."""
-        from app.plugins.builtins.knowledge.services import ask_knowledge
-        from app.core.db import get_worker_session_factory
-        question = arguments.get("question", "")
-        tenant_id = context.get("tenant_id")
-        if not question or not tenant_id:
-            return {"error": "question and tenant_id required"}
-        factory = get_worker_session_factory()
-        async with factory() as db:
-            result = await ask_knowledge(db=db, tenant_id=uuid.UUID(str(tenant_id)), question=question)
-            return {"answer": result.get("answer", ""), "evidence_count": len(result.get("evidence", []))}
-
-    registry.register(
-        name="ask_knowledge",
-        description="Ask a knowledge question. Searches wiki articles and graph relationships for context.",
-        parameters={
-            "type": "object",
-            "properties": {
-                "question": {"type": "string", "description": "The question to ask"},
-            },
-            "required": ["question"],
-        },
-        handler=_ask_knowledge_handler,
-        plugin_name="integration",
-        required_permission="wiki:read",
-        category="knowledge",
-    )
-
-    async def _search_knowledge_handler(arguments: dict[str, Any], context: dict[str, Any]) -> dict[str, Any]:
-        """Search wiki articles via unified search."""
-        from app.plugins.builtins.unified_search.provider_registry import get_search_registry
-        from app.core.db import get_worker_session_factory
-        query = arguments.get("query", "")
-        tenant_id = context.get("tenant_id")
-        if not query or not tenant_id:
-            return {"error": "query and tenant_id required"}
-        factory = get_worker_session_factory()
-        async with factory() as db:
-            registry = get_search_registry()
-            wiki_provider = registry.get("wiki_article")
-            if not wiki_provider:
-                return {"error": "Wiki search provider not available"}
-            results = await wiki_provider._search_fts_filtered(
-                db=db, tsquery=query, tenant_id=uuid.UUID(str(tenant_id)), limit=5, visible_ids=None
-            )
-            return {
-                "results": [
-                    {"title": r.get("title", ""), "summary": (r.get("summary") or r.get("content", "")[:200] or "")}
-                    for r in results
-                ],
-                "count": len(results),
-            }
-
-    registry.register(
-        name="search_knowledge",
-        description="Search wiki articles by keyword. Returns matching articles with title and summary.",
-        parameters={
-            "type": "object",
-            "properties": {
-                "query": {"type": "string", "description": "Search query"},
-            },
-            "required": ["query"],
-        },
-        handler=_search_knowledge_handler,
-        plugin_name="integration",
-        required_permission="wiki:read",
-        category="knowledge",
-    )
-
-    logger.info("Registered integration tools: start_workflow, check_workflow_status, ask_knowledge, search_knowledge")

app/ai/tool_registry.py

@@ -0,0 +1,126 @@
+"""Global tool registry for AI agent tools (core platform service).
+
+Plugins register tools here so AI agents can call them during chat sessions.
+Each tool declares a name, description, JSON schema for parameters,
+and an async handler. Tools can optionally require specific RBAC permissions.
+
+This registry lives in the core AI layer (not inside a plugin) so that the
+agent runtime keeps working regardless of which optional plugins are active.
+Plugins contribute tools via ``register()`` / ``unregister_plugin()`` during
+their activate/deactivate lifecycle.
+"""
+
+from __future__ import annotations
+
+import logging
+from dataclasses import dataclass
+from typing import Any, Protocol
+
+logger = logging.getLogger(__name__)
+
+
+class ToolHandler(Protocol):
+    async def __call__(
+        self,
+        arguments: dict[str, Any],
+        context: dict[str, Any],
+    ) -> str: ...
+
+
+@dataclass
+class AITool:
+    """Represents a tool that an AI agent can call."""
+
+    name: str
+    description: str
+    parameters: dict[str, Any]  # JSON Schema for parameters
+    handler: ToolHandler
+    plugin_name: str = ""
+    required_permission: str | None = None  # e.g. "mail:send"
+    category: str = "general"
+
+    def to_openai_schema(self) -> dict[str, Any]:
+        """Convert to OpenAI function-calling tool schema."""
+        return {
+            "type": "function",
+            "function": {
+                "name": self.name,
+                "description": self.description,
+                "parameters": self.parameters,
+            },
+        }
+
+
+class ToolRegistry:
+    """Singleton registry for AI tools."""
+
+    _instance: ToolRegistry | None = None
+
+    def __new__(cls) -> ToolRegistry:
+        if cls._instance is None:
+            cls._instance = super().__new__(cls)
+            cls._instance._tools: dict[str, AITool] = {}
+        return cls._instance
+
+    def register(
+        self,
+        name: str,
+        description: str,
+        parameters: dict[str, Any],
+        handler: ToolHandler,
+        plugin_name: str = "",
+        required_permission: str | None = None,
+        category: str = "general",
+    ) -> None:
+        """Register a tool."""
+        tool = AITool(
+            name=name,
+            description=description,
+            parameters=parameters,
+            handler=handler,
+            plugin_name=plugin_name,
+            required_permission=required_permission,
+            category=category,
+        )
+        self._tools[name] = tool
+        logger.info("AI tool registered: %s (plugin=%s)", name, plugin_name)
+
+    def unregister(self, name: str) -> None:
+        """Unregister a tool by name."""
+        self._tools.pop(name, None)
+
+    def unregister_plugin(self, plugin_name: str) -> None:
+        """Unregister all tools from a plugin."""
+        to_remove = [
+            name for name, tool in self._tools.items() if tool.plugin_name == plugin_name
+        ]
+        for name in to_remove:
+            self._tools.pop(name, None)
+
+    def get(self, name: str) -> AITool | None:
+        return self._tools.get(name)
+
+    def get_all(self) -> list[AITool]:
+        return list(self._tools.values())
+
+    def get_by_names(self, names: list[str]) -> list[AITool]:
+        return [self._tools[name] for name in names if name in self._tools]
+
+    def list_for_api(self) -> list[dict[str, Any]]:
+        """Return tool list for API response."""
+        return [
+            {
+                "name": tool.name,
+                "description": tool.description,
+                "parameters": tool.parameters,
+                "plugin_name": tool.plugin_name,
+                "required_permission": tool.required_permission,
+                "category": tool.category,
+            }
+            for tool in self._tools.values()
+        ]
+
+
+def get_tool_registry() -> ToolRegistry:
+    """Get the global tool registry singleton."""
+    return ToolRegistry()

app/core/job_registry.py

@@ -46,6 +46,15 @@ def get_job(name: str) -> JobFunc | None:
     return _registry.get(name)
 
 
+def unregister_job(name: str) -> None:
+    """Remove a registered job function (plugin deactivation lifecycle).
+
+    Args:
+        name: The job name to remove.
+    """
+    _registry.pop(name, None)
+
+
 def get_all_jobs() -> list[JobFunc]:
     """Return all registered job functions (order is insertion order).
 

app/core/worker.py

@@ -445,51 +445,9 @@ async def cleanup_trash_job(ctx: dict[str, Any]) -> None:
 register_job("cleanup_trash", cleanup_trash_job)
 
 
-# ── Knowledge retention cleanup job ─────────────────────────────────────────
-
-async def cleanup_knowledge_job(ctx: dict[str, Any]) -> None:
-    """Delete old knowledge extractions (rejected or auto_created) older than 90 days.
-
-    Runs daily. Keeps approved extractions indefinitely.
-    Iterates per-tenant for RLS compliance.
-    """
-    from sqlalchemy import text as sa_text, delete as sa_delete
-    from datetime import datetime, timedelta
-
-    from app.core.db import get_worker_session_factory
-    from app.plugins.builtins.knowledge.models import KnowledgeExtraction
-
-    factory = get_worker_session_factory()
-    async with factory() as db:
-        try:
-            tenant_result = await db.execute(sa_text("SELECT id FROM tenants"))
-            tenant_ids = [row[0] for row in tenant_result]
-
-            cutoff = datetime.utcnow() - timedelta(days=90)
-            total_deleted = 0
-            for tenant_id in tenant_ids:
-                await db.execute(
-                    sa_text("SELECT set_config('app.current_tenant_id', :tid, true)"),
-                    {"tid": str(tenant_id)},
-                )
-                # Delete rejected and auto_created extractions older than 90 days
-                result = await db.execute(
-                    sa_delete(KnowledgeExtraction).where(
-                        KnowledgeExtraction.status.in_(["rejected", "auto_created"]),
-                        KnowledgeExtraction.created_at < cutoff,
-                    )
-                )
-                total_deleted += result.rowcount
-                await db.commit()
-
-            if total_deleted:
-                logger.info("Knowledge retention: cleaned up %d old extractions", total_deleted)
-        except Exception:
-            logger.error("Knowledge retention cleanup failed", exc_info=True)
-            await db.rollback()
-
-
-register_job("cleanup_knowledge", cleanup_knowledge_job)
+# Note: knowledge retention cleanup ("cleanup_knowledge") lives with the
+# knowledge plugin (app/plugins/builtins/knowledge/jobs.py) and is discovered
+# via the plugin job-module mechanism — no core→plugin import.
 
 
 class WorkerSettings:
@@ -531,9 +489,10 @@ class WorkerSettings:
             _wrap_cron_with_lock("cleanup_trash", cleanup_trash_job, ttl_seconds=300),
             hour=4, minute=0,
         ),
-        # Knowledge retention cleanup — daily at 05:00 (90 days, keeps approved)
+        # Knowledge retention cleanup — daily at 05:00 (90 days, keeps approved).
+        # Function comes from the knowledge plugin via the job registry.
         cron(
-            _wrap_cron_with_lock("cleanup_knowledge", cleanup_knowledge_job, ttl_seconds=300),
+            _wrap_cron_with_lock("cleanup_knowledge", get_job("cleanup_knowledge"), ttl_seconds=300),
             hour=5, minute=0,
         ),
         # Scheduled backup — daily at 02:00 (guarded by distributed lock)

app/plugins/builtins/ai_assistant/tool_registry.py

@@ -1,121 +1,19 @@
-"""Global tool registry for AI Assistant plugin tools.
+"""Compatibility shim — the tool registry moved to the core AI layer.
 
-Plugins can register tools that AI agents can call during chat sessions.
-Each tool declares a name, description, JSON schema for parameters,
-and an async handler. Tools can optionally require specific RBAC permissions.
+The agent runtime must not depend on this optional plugin being active,
+so ``ToolRegistry`` / ``AITool`` / ``get_tool_registry`` now live in
+``app.ai.tool_registry``. Import from here still works for existing
+plugin code; new code should import from ``app.ai.tool_registry``
+directly (or via the ai_assistant contract).
 """
 
 from __future__ import annotations
 
-import logging
-from dataclasses import dataclass
-from typing import Any, Protocol
+from app.ai.tool_registry import (  # noqa: F401
+    AITool,
+    ToolHandler,
+    ToolRegistry,
+    get_tool_registry,
+)
 
-logger = logging.getLogger(__name__)
-
-
-class ToolHandler(Protocol):
-    async def __call__(
-        self,
-    arguments: dict[str, Any],
-    context: dict[str, Any],
-    ) -> str: ...
-
-
-@dataclass
-class AITool:
-    """Represents a tool that an AI agent can call."""
-
-    name: str
-    description: str
-    parameters: dict[str, Any]  # JSON Schema for parameters
-    handler: ToolHandler
-    plugin_name: str = ""
-    required_permission: str | None = None  # e.g. "mail:send"
-    category: str = "general"
-
-    def to_openai_schema(self) -> dict[str, Any]:
-        """Convert to OpenAI function-calling tool schema."""
-        return {
-            "type": "function",
-            "function": {
-                "name": self.name,
-                "description": self.description,
-                "parameters": self.parameters,
-            },
-        }
-
-
-class ToolRegistry:
-    """Singleton registry for AI tools."""
-
-    _instance: ToolRegistry | None = None
-
-    def __new__(cls) -> ToolRegistry:
-        if cls._instance is None:
-            cls._instance = super().__new__(cls)
-            cls._instance._tools: dict[str, AITool] = {}
-        return cls._instance
-
-    def register(
-        self,
-    name: str,
-    description: str,
-    parameters: dict[str, Any],
-    handler: ToolHandler,
-    plugin_name: str = "",
-    required_permission: str | None = None,
-    category: str = "general",
-    ) -> None:
-        """Register a tool."""
-        tool = AITool(
-            name=name,
-            description=description,
-            parameters=parameters,
-            handler=handler,
-            plugin_name=plugin_name,
-            required_permission=required_permission,
-            category=category,
-        )
-        self._tools[name] = tool
-        logger.info("AI tool registered: %s (plugin=%s)", name, plugin_name)
-
-    def unregister(self, name: str) -> None:
-        """Unregister a tool by name."""
-        self._tools.pop(name, None)
-
-    def unregister_plugin(self, plugin_name: str) -> None:
-        """Unregister all tools from a plugin."""
-        to_remove = [
-            name for name, tool in self._tools.items() if tool.plugin_name == plugin_name
-        ]
-        for name in to_remove:
-            self._tools.pop(name, None)
-
-    def get(self, name: str) -> AITool | None:
-        return self._tools.get(name)
-
-    def get_all(self) -> list[AITool]:
-        return list(self._tools.values())
-
-    def get_by_names(self, names: list[str]) -> list[AITool]:
-        return [self._tools[name] for name in names if name in self._tools]
-
-    def list_for_api(self) -> list[dict[str, Any]]:
-        """Return tool list for API response."""
-        return [
-            {
-                "name": tool.name,
-                "description": tool.description,
-                "parameters": tool.parameters,
-                "plugin_name": tool.plugin_name,
-                "required_permission": tool.required_permission,
-                "category": tool.category,
-            }
-            for tool in self._tools.values()
-        ]
-
-
-def get_tool_registry() -> ToolRegistry:
-    """Get the global tool registry singleton."""
-    return ToolRegistry()
+__all__ = ["AITool", "ToolHandler", "ToolRegistry", "get_tool_registry"]

app/plugins/builtins/automation/contracts.py

@@ -63,6 +63,11 @@ class AutomationContract:
     # ─── agent_comm ───
     send_agent_message = staticmethod(send_agent_message)
 
+    @classmethod
+    def get_function(cls, name: str):
+        """Return a callable exposed by this contract, or None if absent."""
+        return getattr(cls, name, None)
+
 
 # ─── self-registration ───
 

app/plugins/builtins/automation/plugin.py

@@ -210,12 +210,11 @@ class AutomationPlugin(BasePlugin):
             register_agent_coordinator_tools()
         except Exception:
             logger.exception("Failed to register agent coordinator tools")
-        # Register integration tools (I-AW: Agent→Workflow, I-AK: Agent→Knowledge)
+        # Register workflow agent tools (I-AW: Agent→Workflow)
         try:
-            from app.ai.integration_tools import register_integration_tools
-            register_integration_tools()
+            self._register_workflow_agent_tools()
         except Exception:
-            logger.exception("Failed to register integration tools")
+            logger.exception("Failed to register workflow agent tools")
         # Register MiniApps from manifest
         try:
             from app.plugins.builtins.kommunikation.contracts import get_miniapp_registry
@@ -286,6 +285,94 @@ class AutomationPlugin(BasePlugin):
 
         logger.info("Automation plugin activated")
 
+    def _register_workflow_agent_tools(self) -> None:
+        """Register I-AW agent tools for starting and inspecting workflows."""
+        import uuid
+        from typing import Any
+
+        from app.ai.tool_registry import get_tool_registry
+        registry = get_tool_registry()
+
+        async def _start_workflow_handler(arguments: dict[str, Any], context: dict[str, Any]) -> dict[str, Any]:
+            """Start a workflow by ID."""
+            from app.services.workflow_service import create_instance
+            from app.core.db import get_worker_session_factory
+            workflow_id = arguments.get("workflow_id", "")
+            tenant_id = context.get("tenant_id")
+            user_id = context.get("user_id")
+            if not workflow_id or not tenant_id:
+                return {"error": "workflow_id and tenant_id required"}
+            factory = get_worker_session_factory()
+            async with factory() as db:
+                instance = await create_instance(
+                    db=db,
+                    tenant_id=uuid.UUID(str(tenant_id)),
+                    workflow_id=uuid.UUID(workflow_id),
+                    initiated_by=uuid.UUID(str(user_id)) if user_id else None,
+                )
+                await db.commit()
+                return {"instance_id": str(instance.get("id", "")), "status": instance.get("status", "created")}
+
+        registry.register(
+            name="start_workflow",
+            description="Start a workflow by its ID. Returns the instance ID and status.",
+            parameters={
+                "type": "object",
+                "properties": {
+                    "workflow_id": {"type": "string", "description": "UUID of the workflow to start"},
+                },
+                "required": ["workflow_id"],
+            },
+            handler=_start_workflow_handler,
+            plugin_name=self.manifest.name,
+            required_permission="workflows:read",
+            category="workflow",
+        )
+
+        async def _check_workflow_status_handler(arguments: dict[str, Any], context: dict[str, Any]) -> dict[str, Any]:
+            """Check the status of a workflow instance."""
+            from sqlalchemy import select
+            from app.models.workflow import WorkflowInstance
+            from app.core.db import get_worker_session_factory
+            instance_id = arguments.get("instance_id", "")
+            tenant_id = context.get("tenant_id")
+            if not instance_id or not tenant_id:
+                return {"error": "instance_id and tenant_id required"}
+            factory = get_worker_session_factory()
+            async with factory() as db:
+                result = await db.execute(
+                    select(WorkflowInstance).where(
+                        WorkflowInstance.id == uuid.UUID(instance_id),
+                        WorkflowInstance.tenant_id == uuid.UUID(str(tenant_id)),
+                    )
+                )
+                inst = result.scalar_one_or_none()
+                if not inst:
+                    return {"error": "Instance not found"}
+                return {
+                    "instance_id": str(inst.id),
+                    "status": inst.status,
+                    "current_step": inst.current_step_index,
+                    "completed_at": inst.completed_at.isoformat() if inst.completed_at else None,
+                }
+
+        registry.register(
+            name="check_workflow_status",
+            description="Check the status of a workflow instance by its ID.",
+            parameters={
+                "type": "object",
+                "properties": {
+                    "instance_id": {"type": "string", "description": "UUID of the workflow instance"},
+                },
+                "required": ["instance_id"],
+            },
+            handler=_check_workflow_status_handler,
+            plugin_name=self.manifest.name,
+            required_permission="workflows:read",
+            category="workflow",
+        )
+        logger.info("Registered workflow agent tools: start_workflow, check_workflow_status")
+
     async def on_deactivate(self, db, service_container, event_bus) -> None:
         """Clean up on deactivation."""
         # Contract abmelden
@@ -307,6 +394,13 @@ class AutomationPlugin(BasePlugin):
             unregister_agent_coordinator_tools()
         except Exception:
             logger.exception("Failed to unregister agent coordinator tools")
+        # Unregister workflow agent tools from the core AI tool registry
+        try:
+            from app.ai.tool_registry import get_tool_registry
+            get_tool_registry().unregister_plugin(self.manifest.name)
+            logger.info("Unregistered AI agent tools for plugin '%s'", self.manifest.name)
+        except Exception:
+            logger.exception("Failed to unregister AI agent tools")
         # Unregister MiniApps
         try:
             from app.plugins.builtins.kommunikation.contracts import get_miniapp_registry

app/plugins/builtins/calendar/contracts.py

@@ -15,6 +15,11 @@ class CalendarContract:
     CalendarEntry = CalendarEntry
     CalendarEntryLink = CalendarEntryLink
 
+    @classmethod
+    def get_function(cls, name: str):
+        """Return a callable exposed by this contract, or None if absent."""
+        return getattr(cls, name, None)
+
 
 # ─── self-registration ───
 

app/plugins/builtins/dms/contracts.py

@@ -15,6 +15,11 @@ class DmsContract:
     DmsFile = DmsFile
     Folder = Folder
 
+    @classmethod
+    def get_function(cls, name: str):
+        """Return a callable exposed by this contract, or None if absent."""
+        return getattr(cls, name, None)
+
 
 # ─── self-registration ───
 

app/plugins/builtins/knowledge/jobs.py

@@ -0,0 +1,62 @@
+"""ARQ background jobs for the knowledge plugin.
+
+Registered via ``register_job()`` at import time; the worker discovers this
+module through ``KnowledgePlugin.get_job_modules()`` — no core imports of
+plugin models needed.
+"""
+
+from __future__ import annotations
+
+import logging
+from datetime import UTC, datetime, timedelta
+from typing import Any
+
+from app.core.job_registry import register_job
+from app.plugins.builtins.knowledge.models import KnowledgeExtraction
+
+logger = logging.getLogger(__name__)
+
+_KNOWLEDGE_RETENTION_DAYS = 90
+
+
+async def cleanup_knowledge_job(ctx: dict[str, Any]) -> None:
+    """Delete old knowledge extractions (rejected or auto_created) older than 90 days.
+
+    Runs daily. Keeps approved extractions indefinitely.
+    Iterates per-tenant for RLS compliance.
+    """
+    from sqlalchemy import text as sa_text, delete as sa_delete
+
+    from app.core.db import get_worker_session_factory
+
+    factory = get_worker_session_factory()
+    async with factory() as db:
+        try:
+            tenant_result = await db.execute(sa_text("SELECT id FROM tenants"))
+            tenant_ids = [row[0] for row in tenant_result]
+
+            cutoff = datetime.now(UTC).replace(tzinfo=None) - timedelta(days=_KNOWLEDGE_RETENTION_DAYS)
+            total_deleted = 0
+            for tenant_id in tenant_ids:
+                await db.execute(
+                    sa_text("SELECT set_config('app.current_tenant_id', :tid, true)"),
+                    {"tid": str(tenant_id)},
+                )
+                # Delete rejected and auto_created extractions older than retention window
+                result = await db.execute(
+                    sa_delete(KnowledgeExtraction).where(
+                        KnowledgeExtraction.status.in_(["rejected", "auto_created"]),
+                        KnowledgeExtraction.created_at < cutoff,
+                    )
+                )
+                total_deleted += result.rowcount
+                await db.commit()
+
+            if total_deleted:
+                logger.info("Knowledge retention: cleaned up %d old extractions", total_deleted)
+        except Exception:
+            logger.error("Knowledge retention cleanup failed", exc_info=True)
+            await db.rollback()
+
+
+register_job("cleanup_knowledge", cleanup_knowledge_job)

app/plugins/builtins/knowledge/plugin.py

@@ -1,6 +1,8 @@
 """Knowledge plugin — LLM-based entity/relationship extraction, ask-knowledge, review queue."""
 from __future__ import annotations
 import logging
+import uuid
+from typing import Any
 from app.plugins.base import BasePlugin
 from app.plugins.manifest import PluginManifest, PluginRouteDef
 
@@ -59,9 +61,101 @@ class KnowledgePlugin(BasePlugin):
             logger.info("Registered knowledge extraction hooks")
         except Exception:
             logger.exception("Failed to register knowledge hooks")
+        # Register knowledge agent tools (I-AK: Agent→Knowledge)
+        try:
+            self._register_knowledge_agent_tools()
+        except Exception:
+            logger.exception("Failed to register knowledge agent tools")
+
+    def _register_knowledge_agent_tools(self) -> None:
+        """Register I-AK agent tools for asking and searching knowledge."""
+        from app.ai.tool_registry import get_tool_registry
+        registry = get_tool_registry()
+
+        async def _ask_knowledge_handler(arguments: dict[str, Any], context: dict[str, Any]) -> dict[str, Any]:
+            """Ask a knowledge question."""
+            from app.plugins.builtins.knowledge.services import ask_knowledge
+            from app.core.db import get_worker_session_factory
+            question = arguments.get("question", "")
+            tenant_id = context.get("tenant_id")
+            if not question or not tenant_id:
+                return {"error": "question and tenant_id required"}
+            factory = get_worker_session_factory()
+            async with factory() as db:
+                result = await ask_knowledge(db=db, tenant_id=uuid.UUID(str(tenant_id)), question=question)
+                return {"answer": result.get("answer", ""), "evidence_count": len(result.get("evidence", []))}
+
+        registry.register(
+            name="ask_knowledge",
+            description="Ask a knowledge question. Searches wiki articles and graph relationships for context.",
+            parameters={
+                "type": "object",
+                "properties": {
+                    "question": {"type": "string", "description": "The question to ask"},
+                },
+                "required": ["question"],
+            },
+            handler=_ask_knowledge_handler,
+            plugin_name=self.manifest.name,
+            required_permission="wiki:read",
+            category="knowledge",
+        )
+
+        async def _search_knowledge_handler(arguments: dict[str, Any], context: dict[str, Any]) -> dict[str, Any]:
+            """Search wiki articles via unified search."""
+            from app.plugins.builtins.unified_search.provider_registry import get_search_registry
+            from app.core.db import get_worker_session_factory
+            query = arguments.get("query", "")
+            tenant_id = context.get("tenant_id")
+            if not query or not tenant_id:
+                return {"error": "query and tenant_id required"}
+            factory = get_worker_session_factory()
+            async with factory() as db:
+                search_registry = get_search_registry()
+                wiki_provider = search_registry.get("wiki_article")
+                if not wiki_provider:
+                    return {"error": "Wiki search provider not available"}
+                results = await wiki_provider._search_fts_filtered(
+                    db=db, tsquery=query, tenant_id=uuid.UUID(str(tenant_id)), limit=5, visible_ids=None
+                )
+                return {
+                    "results": [
+                        {"title": r.get("title", ""), "summary": (r.get("summary") or r.get("content", "")[:200] or "")}
+                        for r in results
+                    ],
+                    "count": len(results),
+                }
+
+        registry.register(
+            name="search_knowledge",
+            description="Search wiki articles by keyword. Returns matching articles with title and summary.",
+            parameters={
+                "type": "object",
+                "properties": {
+                    "query": {"type": "string", "description": "Search query"},
+                },
+                "required": ["query"],
+            },
+            handler=_search_knowledge_handler,
+            plugin_name=self.manifest.name,
+            required_permission="wiki:read",
+            category="knowledge",
+        )
+        logger.info("Registered knowledge agent tools: ask_knowledge, search_knowledge")
+
+    def get_job_modules(self) -> list[str]:
+        """ARQ job modules — the retention cleanup job lives with this plugin."""
+        return ["app.plugins.builtins.knowledge.jobs"]
 
     async def on_deactivate(self, db, service_container, event_bus) -> None:
         """Clean up on deactivation."""
         from app.core.hooks import unregister_actions_by_owner
         unregister_actions_by_owner("knowledge")
+        # Unregister knowledge agent tools from the core AI tool registry
+        try:
+            from app.ai.tool_registry import get_tool_registry
+            get_tool_registry().unregister_plugin(self.manifest.name)
+            logger.info("Unregistered AI agent tools for plugin '%s'", self.manifest.name)
+        except Exception:
+            logger.exception("Failed to unregister AI agent tools")
         await super().on_deactivate(db, service_container, event_bus)

app/plugins/builtins/kommunikation/contracts.py

@@ -31,6 +31,7 @@ from app.plugins.builtins.kommunikation.participant_registry import (
 )
 from app.plugins.builtins.kommunikation.services import (
     create_plugin_room,
+    find_locked_room_id,
     get_conversation,
     get_messages,
     parse_mentions,
@@ -55,6 +56,7 @@ class KommunikationContract:
     get_messages = staticmethod(get_messages)
     send_message = staticmethod(send_message)
     create_plugin_room = staticmethod(create_plugin_room)
+    find_locked_room_id = staticmethod(find_locked_room_id)
 
     # ─── participant registry ───
     get_participant_registry = staticmethod(get_participant_registry)
@@ -92,6 +94,7 @@ __all__ = [
     "get_messages",
     "send_message",
     "create_plugin_room",
+    "find_locked_room_id",
     "CommConversation",
     "CommMessage",
     "CommParticipant",

app/plugins/builtins/kommunikation/services.py

@@ -1047,6 +1047,30 @@ async def _get_unread_count(
 # ─── Plugin Room Creation ───
 
 
+async def find_locked_room_id(
+    db: AsyncSession,
+    tenant_id: uuid.UUID,
+    plugin_name: str,
+    title: str,
+) -> uuid.UUID | None:
+    """Find the conversation ID of a locked plugin room by tenant and title.
+
+    Matches the same room semantics as ``create_plugin_room``: locked rooms
+    are owned by the plugin (``locked_by == plugin_name``) and soft-deleted
+    conversations are excluded. Returns ``None`` when no room exists.
+    """
+    result = await db.execute(
+        select(CommConversation.id).where(
+            CommConversation.tenant_id == tenant_id,
+            CommConversation.title == title,
+            CommConversation.is_locked.is_(True),
+            CommConversation.locked_by == plugin_name,
+            CommConversation.deleted_at.is_(None),
+        )
+    )
+    return result.scalar_one_or_none()
+
+
 async def create_plugin_room(
     db: AsyncSession,
     tenant_id: uuid.UUID,

app/plugins/builtins/mail/contracts.py

@@ -32,6 +32,11 @@ class MailContract:
     # ─── models ───
     Mail = Mail
 
+    @classmethod
+    def get_function(cls, name: str):
+        """Return a callable exposed by this contract, or None if absent."""
+        return getattr(cls, name, None)
+
 
 # ─── self-registration ───
 

app/plugins/builtins/unified_search/contracts.py

@@ -10,6 +10,33 @@ from app.plugins.builtins.unified_search.query_understanding import llm_analyze_
 from app.plugins.builtins.unified_search.search_engine import find_similar_all_types, hybrid_search
 
 
+async def simple_search(
+    db: Any,
+    query: str,
+    tenant_id: Any,
+    entity_types: list[str] | None = None,
+    limit: int = 20,
+    user_id: Any | None = None,
+    is_system_admin: bool = False,
+) -> list[dict[str, Any]]:
+    """Convenience search entry point: analyze a raw query string and run
+    the hybrid search over all registered providers.
+
+    Falls back to a plain normalized-query analysis when the LLM is
+    unavailable.
+    """
+    analysis = await llm_analyze_query(query, db=db, tenant_id=tenant_id)
+    return await hybrid_search(
+        db=db,
+        query_analysis=analysis,
+        tenant_id=tenant_id,
+        entity_types=entity_types,
+        limit=limit,
+        user_id=user_id,
+        is_system_admin=is_system_admin,
+    )
+
+
 class UnifiedSearchContract:
     """Public contract for the unified_search plugin."""
 
@@ -20,8 +47,14 @@ class UnifiedSearchContract:
     find_similar_all_types = staticmethod(find_similar_all_types)
     get_search_registry = staticmethod(get_search_registry)
     llm_analyze_query = staticmethod(llm_analyze_query)
+    simple_search = staticmethod(simple_search)
     BaseSearchProvider = BaseSearchProvider
 
+    @classmethod
+    def get_function(cls, name: str):
+        """Return a callable exposed by this contract, or None if absent."""
+        return getattr(cls, name, None)
+
 
 # ─── self-registration ───
 

app/routes/compliance.py

@@ -19,11 +19,21 @@ from app.core.db import get_db
 from app.deps import require_permission
 from app.models.audit import AuditLog
 from app.models.compliance import ComplianceIncident
-from app.plugins.builtins.automation.models import AgentDefinition
+from app.plugins.builtins.contracts import get_contract as _get_automation_contract
 
 router = APIRouter(prefix="/api/v1/compliance", tags=["compliance"])
 
 
+def _get_agent_definition_model():
+    """Resolve the AgentDefinition model via the automation contract.
+
+    Returns ``None`` when the automation plugin is not active — callers
+    respond with 503 instead of failing at import time.
+    """
+    contract = _get_automation_contract("automation")
+    return getattr(contract, "AgentDefinition", None) if contract else None
+
+
 # ─── Schemas ───
 
 
@@ -160,13 +170,17 @@ async def list_ai_registry(
     """List all AI agents with their use-case metadata. Admin only."""
     tenant_id = uuid.UUID(current_user["tenant_id"])
 
+    agent_model = _get_agent_definition_model()
+    if agent_model is None:
+        raise HTTPException(503, detail={"detail": "Automation plugin not active", "code": "plugin_inactive"})
+
     q = (
-        select(AgentDefinition)
+        select(agent_model)
         .where(
-            AgentDefinition.tenant_id == tenant_id,
-            AgentDefinition.deleted_at.is_(None),
+            agent_model.tenant_id == tenant_id,
+            agent_model.deleted_at.is_(None),
         )
-        .order_by(AgentDefinition.name)
+        .order_by(agent_model.name)
     )
     result = await db.execute(q)
     agents = result.scalars().all()
@@ -214,10 +228,14 @@ async def get_dpia_template(
     except ValueError:
         raise HTTPException(400, detail={"detail": "Invalid agent_id", "code": "invalid_id"}) from None
 
-    q = select(AgentDefinition).where(
-        AgentDefinition.id == aid,
-        AgentDefinition.tenant_id == tenant_id,
-        AgentDefinition.deleted_at.is_(None),
+    agent_model = _get_agent_definition_model()
+    if agent_model is None:
+        raise HTTPException(503, detail={"detail": "Automation plugin not active", "code": "plugin_inactive"})
+
+    q = select(agent_model).where(
+        agent_model.id == aid,
+        agent_model.tenant_id == tenant_id,
+        agent_model.deleted_at.is_(None),
     )
     result = await db.execute(q)
     agent = result.scalar_one_or_none()

app/workflows/engine.py

@@ -92,22 +92,16 @@ class WorkflowEngine:
             # Post workflow completion to Communication (G-WORK)
             try:
                 from app.plugins.builtins.contracts import get_contract_registry
-                from app.plugins.builtins.kommunikation.models import CommConversation
-                from sqlalchemy import select as sa_select
                 komm = get_contract_registry().get("kommunikation")
                 if komm and instance.initiated_by:
                     room_title = f"Workflow: {workflow.name if hasattr(workflow, 'name') else str(instance.workflow_id)}"
-                    existing = await self.db.execute(
-                        sa_select(CommConversation).where(
-                            CommConversation.tenant_id == self.tenant_id,
-                            CommConversation.title == room_title,
-                            CommConversation.is_locked.is_(True),
-                            CommConversation.locked_by == "workflow",
-                            CommConversation.deleted_at.is_(None),
-                        )
+                    conv_id = await komm.find_locked_room_id(
+                        db=self.db,
+                        tenant_id=self.tenant_id,
+                        plugin_name="workflow",
+                        title=room_title,
                     )
-                    conv = existing.scalar_one_or_none()
-                    if not conv:
+                    if not conv_id:
                         room = await komm.create_plugin_room(
                             db=self.db,
                             tenant_id=self.tenant_id,
@@ -117,8 +111,6 @@ class WorkflowEngine:
                             participant_type="workflow",
                         )
                         conv_id = uuid.UUID(room["conversation_id"])
-                    else:
-                        conv_id = conv.id
                     await komm.send_message(
                         db=self.db,
                         tenant_id=self.tenant_id,

app/workflows/step_handlers.py

@@ -61,6 +61,11 @@ def register_step_type(step_type: str):
     return decorator
 
 
+def unregister_step_type(step_type: str) -> None:
+    """Remove a step handler (plugin deactivation lifecycle symmetry)."""
+    _HANDLERS.pop(step_type, None)
+
+
 def get_step_handler(step_type: str) -> StepHandler | None:
     return _HANDLERS.get(step_type)
 
@@ -218,11 +223,13 @@ async def _handle_mail(
         return StepResult(error="mail step requires to and subject", abort=True)
 
     try:
-        from app.plugins.builtins.mail.contracts import MailContract
-        contract = MailContract
+        from app.plugins.builtins.contracts import get_contract
+        contract = get_contract("mail")
+        if contract is None:
+            return StepResult(error="mail plugin not available", abort=True)
         send_fn = contract.get_function("send_email")
         if send_fn is None:
-            return StepResult(error="mail plugin not available", abort=True)
+            return StepResult(error="mail send_email not exposed via contract yet", abort=True)
 
         result = await send_fn(
             db=db,
@@ -258,12 +265,14 @@ async def _handle_calendar(
     action = config.get("action", "create")
 
     try:
-        from app.plugins.builtins.calendar.contracts import CalendarContract
-        contract = CalendarContract
+        from app.plugins.builtins.contracts import get_contract
+        contract = get_contract("calendar")
+        if contract is None:
+            return StepResult(error="calendar plugin not available", abort=True)
         if action == "create":
             fn = contract.get_function("create_event")
             if fn is None:
-                return StepResult(error="calendar plugin not available", abort=True)
+                return StepResult(error="calendar create_event not exposed via contract yet", abort=True)
             result = await fn(
                 db=db,
                 tenant_id=tenant_id,
@@ -275,7 +284,7 @@ async def _handle_calendar(
         elif action == "delete":
             fn = contract.get_function("delete_event")
             if fn is None:
-                return StepResult(error="calendar plugin not available", abort=True)
+                return StepResult(error="calendar delete_event not exposed via contract yet", abort=True)
             await fn(db=db, tenant_id=tenant_id, event_id=config.get("event_id", ""))
             return StepResult()
         else:
@@ -303,19 +312,21 @@ async def _handle_dms(
     action = config.get("action", "search")
 
     try:
-        from app.plugins.builtins.dms.contracts import DmsContract
-        contract = DmsContract
+        from app.plugins.builtins.contracts import get_contract
+        contract = get_contract("dms")
+        if contract is None:
+            return StepResult(error="dms plugin not available", abort=True)
 
         if action == "search":
             fn = contract.get_function("search_files")
             if fn is None:
-                return StepResult(error="dms plugin not available", abort=True)
+                return StepResult(error="dms search_files not exposed via contract yet", abort=True)
             results = await fn(db=db, tenant_id=tenant_id, query=config.get("query", ""))
             return StepResult(output={"files": results} if results else {})
         elif action == "metadata":
             fn = contract.get_function("get_file_metadata")
             if fn is None:
-                return StepResult(error="dms plugin not available", abort=True)
+                return StepResult(error="dms get_file_metadata not exposed via contract yet", abort=True)
             metadata = await fn(db=db, tenant_id=tenant_id, file_id=config.get("file_id", ""))
             return StepResult(output={"metadata": metadata} if metadata else {})
         else:
@@ -348,17 +359,16 @@ async def _handle_search(
         return StepResult(error="search step requires query", abort=True)
 
     try:
-        from app.plugins.builtins.unified_search.contracts import SearchContract
-        contract = SearchContract
-        fn = contract.get_function("unified_search")
-        if fn is None:
+        from app.plugins.builtins.contracts import get_contract
+        contract = get_contract("unified_search")
+        if contract is None:
             return StepResult(error="search plugin not available", abort=True)
-        results = await fn(
+        results = await contract.simple_search(
             db=db,
-            tenant_id=tenant_id,
             query=query,
-            entity_type=entity_type,
-            limit=limit,
+            tenant_id=tenant_id,
+            entity_types=[entity_type] if entity_type else None,
+            limit=int(limit),
         )
         # Store results in context for later steps
         instance.context["search_results"] = results
@@ -391,17 +401,21 @@ async def _handle_agent(
         return StepResult(error="agent step requires agent_id", abort=True)
 
     try:
-        from app.plugins.builtins.automation.contracts import AutomationContract
-        contract = AutomationContract
+        from app.plugins.builtins.contracts import get_contract
+        contract = get_contract("automation")
+        if contract is None:
+            return StepResult(error="automation plugin not available", abort=True)
         fn = contract.get_function("run_agent")
         if fn is None:
-            return StepResult(error="automation plugin not available", abort=True)
+            return StepResult(error="automation run_agent not exposed via contract yet", abort=True)
+        # run_agent is an ARQ job function: it opens its own DB session and runs
+        # the agent loop to completion, so ``wait`` always ends up true here.
+        logger.debug("agent step wait_for_completion=%s (step always waits)", wait)
         result = await fn(
-            db=db,
-            tenant_id=tenant_id,
-            agent_id=uuid.UUID(agent_id),
-            input_data=user_input,
-            wait_for_completion=wait,
+            {},
+            str(agent_id),
+            trigger_type="workflow",
+            trigger_data={"input": user_input},
         )
         instance.context["agent_result"] = result
         return StepResult(output={"agent_result": result} if result else {})

frontend/src/components/comm/blocks/BlockRenderer.tsx

@@ -6,14 +6,8 @@ import ImageBlock from './ImageBlock';
 import AudioBlock from './AudioBlock';
 import VideoBlock from './VideoBlock';
 import FileBlock from './FileBlock';
-import ActionCardBlock from './ActionCardBlock';
-import ContactCardBlock from './ContactCardBlock';
-import MiniAppBlock from './MiniAppBlock';
-import AgentResultBlock from './AgentResultBlock';
-import ApprovalRequestBlock from './ApprovalRequestBlock';
-import TaskCardBlock from './TaskCardBlock';
-import WorkflowCardBlock from './WorkflowCardBlock';
-import KnowledgeCardBlock from './KnowledgeCardBlock';
+import { getBlockComponent } from './registry';
+import './registrations'; // plugin-contributed block registrations
 
 interface BlockRendererProps {
   blocks: MessageBlock[];
@@ -51,29 +45,20 @@ const BlockRenderer: React.FC<BlockRendererProps> = ({ blocks }) => {
               return <VideoBlock block={block} />;
             case 'file':
               return <FileBlock block={block} />;
-            case 'action_card':
-              return <ActionCardBlock block={block} />;
-            case 'contact_card':
-              return <ContactCardBlock block={block} />;
-            case 'miniapp':
-              return <MiniAppBlock block={block} />;
-            case 'agent_result':
-              return <AgentResultBlock block={block} />;
-            case 'approval_request':
-              return <ApprovalRequestBlock block={block} />;
-            case 'task_card':
-              return <TaskCardBlock block={block} />;
-            case 'workflow_card':
-              return <WorkflowCardBlock block={block} />;
-            case 'knowledge_card':
-              return <KnowledgeCardBlock block={block} />;
-            default:
+            default: {
+              // Plugin-contributed block types (Block H / HC-F)
+              const Contributed = getBlockComponent(block.block_type);
+              if (Contributed) {
+                const ContributedBlock = Contributed as React.FC<{ block: MessageBlock }>;
+                return <ContributedBlock block={block} />;
+              }
               // Fallback for unknown block types
               return (
                 <div className="text-xs text-secondary-400 italic p-2 rounded bg-secondary-50">
                   Unbekannter Block-Typ: {block.block_type}
                 </div>
               );
+            }
           }
         };
 

frontend/src/components/comm/blocks/registrations.ts

@@ -0,0 +1,26 @@
+/**
+ * Plugin block registrations.
+ *
+ * Currently a static import list; the dynamic plugin loader (ARCH-019 fix)
+ * will replace this file with manifest-driven registration. Plugins register
+ * their block renderers via ``registerBlockType`` with an owner tag so that
+ * ``unregisterBlockTypes(owner)`` can clean up on deactivation.
+ */
+import { registerBlockType } from './registry';
+import ActionCardBlock from './ActionCardBlock';
+import ContactCardBlock from './ContactCardBlock';
+import MiniAppBlock from './MiniAppBlock';
+import AgentResultBlock from './AgentResultBlock';
+import ApprovalRequestBlock from './ApprovalRequestBlock';
+import TaskCardBlock from './TaskCardBlock';
+import WorkflowCardBlock from './WorkflowCardBlock';
+import KnowledgeCardBlock from './KnowledgeCardBlock';
+
+registerBlockType('action_card', ActionCardBlock, 'core-comm');
+registerBlockType('contact_card', ContactCardBlock, 'contacts');
+registerBlockType('miniapp', MiniAppBlock, 'kommunikation');
+registerBlockType('agent_result', AgentResultBlock, 'automation');
+registerBlockType('approval_request', ApprovalRequestBlock, 'core-approvals');
+registerBlockType('task_card', TaskCardBlock, 'tasks');
+registerBlockType('workflow_card', WorkflowCardBlock, 'workflows');
+registerBlockType('knowledge_card', KnowledgeCardBlock, 'knowledge');

frontend/src/components/comm/blocks/registry.ts

@@ -0,0 +1,36 @@
+/**
+ * Message block type registry.
+ *
+ * Core owns the base block types; plugins can contribute additional block
+ * renderers via ``registerBlockType`` / ``unregisterBlockTypes`` during their
+ * frontend activation lifecycle (Block H / HC-F).
+ */
+import type { ComponentType } from 'react';
+import type { MessageBlock } from '@/store/commStore';
+
+export type BlockComponent = ComponentType<{ block: MessageBlock }>;
+
+const _registry = new Map<string, BlockComponent>();
+
+export function registerBlockType(blockType: string, component: BlockComponent, owner = ''): void {
+  if (_registry.has(blockType)) {
+    // eslint-disable-next-line no-console
+    console.warn(`[blockRegistry] block type '${blockType}' re-registered by '${owner || 'unknown'}' — overwriting`);
+  }
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  (component as any).__block_owner__ = owner;
+  _registry.set(blockType, component);
+}
+
+export function unregisterBlockTypes(owner: string): void {
+  for (const [key, component] of _registry.entries()) {
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    if ((component as any).__block_owner__ === owner) {
+      _registry.delete(key);
+    }
+  }
+}
+
+export function getBlockComponent(blockType: string): BlockComponent | undefined {
+  return _registry.get(blockType);
+}

frontend/src/components/layout/AISidebar.tsx

@@ -5,6 +5,7 @@ import { SuggestionList } from '@/components/ai/SuggestionSidebar';
 import { ImprovementPanel } from '@/components/ai/ImprovementPanel';
 import { createSession, fetchSessions } from '@/api/ai';
 import { useUIStore } from '@/store/uiStore';
+import { getContributedTabs } from './sidebarTabs';
 import { useTranslation } from 'react-i18next';
 import { useUsers, useGroups } from '@/api/hooks';
 import { Avatar } from '@/components/ui/Avatar';
@@ -35,7 +36,7 @@ const chevronRightIcon = (
 );
 
 interface TabDef {
-  key: 'proactive' | 'chat' | 'notifications' | 'team' | 'chatroom';
+  key: string;
   label: string;
   icon: (cls: string) => React.ReactNode;
   testId: string;
@@ -139,6 +140,13 @@ export function AISidebar() {
     { key: 'notifications', label: t('topbar.notifications'), icon: bellIcon, testId: 'ai-sidebar-tab-notifications' },
     { key: 'team', label: 'Team', icon: teamIcon, testId: 'ai-sidebar-tab-team' },
     { key: 'chatroom', label: 'Chat', icon: chatBubbleIcon, testId: 'ai-sidebar-tab-chatroom' },
+    // Plugin-contributed tabs (Block H / HC-G)
+    ...getContributedTabs().map((ct) => ({
+      key: ct.key,
+      label: ct.label,
+      icon: ct.icon,
+      testId: ct.testId,
+    })),
   ];
 
   const activeTab = tabs.find((tab) => tab.key === aiSidebarTab) || tabs[0];
@@ -209,6 +217,12 @@ export function AISidebar() {
     if (aiSidebarTab === 'chatroom') {
       return <ChatPanel />;
     }
+    // Plugin-contributed tabs (Block H / HC-G)
+    const contributed = getContributedTabs().find((ct) => ct.key === aiSidebarTab);
+    if (contributed) {
+      const ContributedComponent = contributed.component;
+      return <ContributedComponent />;
+    }
     // chat tab
     if (loading) {
       return (

frontend/src/components/layout/sidebarTabs.ts

@@ -0,0 +1,42 @@
+/**
+ * AI sidebar tab registry.
+ *
+ * Core owns the base tabs (chat/proactive/notifications/team/chatroom);
+ * plugins contribute additional tabs via ``registerSidebarTab`` during their
+ * frontend activation lifecycle (Block H / HC-G). Contributed tabs render a
+ * generic container component provided by the plugin.
+ */
+import type { ComponentType } from 'react';
+
+type IconFn = (className: string) => JSX.Element;
+
+export interface ContributedTab {
+  key: string;
+  label: string;
+  icon: IconFn;
+  testId: string;
+  component: ComponentType;
+}
+
+const _tabs = new Map<string, ContributedTab>();
+
+export function registerSidebarTab(tab: ContributedTab): void {
+  if (_tabs.has(tab.key)) {
+    // eslint-disable-next-line no-console
+    console.warn(`[sidebarTabs] tab '${tab.key}' re-registered — overwriting`);
+  }
+  _tabs.set(tab.key, tab);
+}
+
+export function unregisterSidebarTabs(owner: string): void {
+  for (const [key, tab] of _tabs.entries()) {
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    if ((tab.component as any).__sidebar_owner__ === owner) {
+      _tabs.delete(key);
+    }
+  }
+}
+
+export function getContributedTabs(): ContributedTab[] {
+  return Array.from(_tabs.values());
+}

frontend/src/store/uiStore.ts

@@ -2,7 +2,9 @@ import { create } from 'zustand';
 
 export type Theme = 'light' | 'dark' | 'system';
 export type Locale = 'de' | 'en';
-export type AISidebarTab = 'proactive' | 'chat' | 'notifications' | 'team' | 'chatroom';
+// Plugin-contributed tabs add arbitrary keys (Block H / HC-G) — the union
+// keeps autocomplete for the base tabs while allowing any string key.
+export type AISidebarTab = 'proactive' | 'chat' | 'notifications' | 'team' | 'chatroom' | (string & {});
 
 export interface Toast {
   id: string;

tests/test_gate_h.py

@@ -0,0 +1,169 @@
+"""Gate H — prove that a plugin contributes ALL extension points without
+changing a single core file.
+
+Covers:
+1. Agent tool  -> app.ai.tool_registry (core layer)
+2. Workflow step type -> app.workflows.step_handlers
+3. Fallback intent -> app.ai.action_mapper
+4. Deactivate symmetry -> everything removed again
+5. Re-activate -> present again, NO duplicates
+
+The plugin under test is defined INLINE in this file — if this test passes,
+no core file had to be touched to extend the platform.
+"""
+
+from __future__ import annotations
+
+from typing import Any
+
+import pytest
+
+# ─── The Gate-H test plugin (inline — zero core changes) ─────────────────────
+
+
+def _build_gate_h_plugin():
+    from app.plugins.base import BasePlugin
+    from app.plugins.manifest import PluginManifest
+
+    class GateHTestPlugin(BasePlugin):
+        """Minimal plugin exercising every Block-H contribution point."""
+
+        manifest = PluginManifest(
+            name="gate_h_test",
+            version="1.0.0",
+            display_name="Gate H Test",
+            description="Proves plugin contributions without core changes.",
+            dependencies=[],
+            routes=[],
+            events=[],
+            migrations=[],
+            permissions=["gate_h_test:read"],
+        )
+
+        async def on_activate(self, db, service_container, event_bus) -> None:
+            await super().on_activate(db, service_container, event_bus)
+
+            # 1) Agent tool via CORE registry
+            from app.ai.tool_registry import get_tool_registry
+
+            async def _echo_handler(arguments: dict[str, Any], context: dict[str, Any]) -> str:
+                return f"gate-h says: {arguments.get('text', '')}"
+
+            get_tool_registry().register(
+                name="gate_h_echo",
+                description="Echo text back (Gate H proof).",
+                parameters={
+                    "type": "object",
+                    "properties": {"text": {"type": "string"}},
+                    "required": ["text"],
+                },
+                handler=_echo_handler,
+                plugin_name=self.manifest.name,
+                required_permission=None,
+                category="test",
+            )
+
+            # 2) Workflow step type
+            from app.workflows.step_handlers import StepResult, register_step_type
+
+            @register_step_type("gate_h_noop")
+            async def _handle_gate_h_noop(db, tenant_id, instance, step):  # noqa: ANN001
+                return StepResult(output={"gate_h": True})
+
+            # 3) Fallback intent pattern
+            from app.ai.action_mapper import register_intent_pattern
+
+            def _invoice_intent(query: str, context: dict[str, Any] | None):
+                return [
+                    {
+                        "method": "POST",
+                        "path": "/api/v1/gate-h/invoices",
+                        "body": {},
+                        "description": "Create invoice (Gate H proof)",
+                        "confidence": 0.9,
+                    }
+                ]
+
+            _invoice_intent.owner_tag = self.manifest.name
+            register_intent_pattern(r"\b(create|new)\b.*\binvoice\b", _invoice_intent, owner=self.manifest.name)
+
+        async def on_deactivate(self, db, service_container, event_bus) -> None:
+            # Symmetry: remove everything registered above
+            from app.ai.tool_registry import get_tool_registry
+            from app.workflows.step_handlers import unregister_step_type
+            from app.ai.action_mapper import unregister_intent_patterns
+
+            get_tool_registry().unregister_plugin(self.manifest.name)
+            unregister_step_type("gate_h_noop")
+            unregister_intent_patterns(self.manifest.name)
+            await super().on_deactivate(db, service_container, event_bus)
+
+    return GateHTestPlugin
+
+
+# ─── The proof ────────────────────────────────────────────────────────────────
+
+
+@pytest.mark.asyncio
+async def test_gate_h_full_contribution_lifecycle():
+    """Activate -> contributed everywhere; deactivate -> gone; reactivate -> back, no dupes."""
+    from app.ai.tool_registry import get_tool_registry
+    from app.workflows.step_handlers import get_step_handler
+    from app.ai.action_mapper import map_query_to_actions
+
+    plugin_cls = _build_gate_h_plugin()
+    plugin = plugin_cls()
+
+    # ── Before activation: nothing registered ──
+    assert get_tool_registry().get("gate_h_echo") is None
+    assert get_step_handler("gate_h_noop") is None
+    assert map_query_to_actions("create invoice for Acme") == []
+
+    # ── Activate ──
+    await plugin.on_activate(db=None, service_container=None, event_bus=None)
+
+    # 1) Agent tool present in CORE registry
+    tool = get_tool_registry().get("gate_h_echo")
+    assert tool is not None
+    assert tool.plugin_name == "gate_h_test"
+    result = await tool.handler({"text": "hello"}, {})
+    assert result == "gate-h says: hello"
+
+    # 2) Workflow step type resolvable
+    handler = get_step_handler("gate_h_noop")
+    assert handler is not None
+
+    # 3) Intent contributes actions for a FACHMODUL term unknown to core
+    actions = map_query_to_actions("create invoice for Acme")
+    assert len(actions) == 1
+    assert actions[0]["path"] == "/api/v1/gate-h/invoices"
+
+    # ── Deactivate: full symmetry ──
+    await plugin.on_deactivate(db=None, service_container=None, event_bus=None)
+    assert get_tool_registry().get("gate_h_echo") is None
+    assert get_step_handler("gate_h_noop") is None
+    assert map_query_to_actions("create invoice for Acme") == []
+
+    # ── Re-activate: back AND no duplicates ──
+    await plugin.on_activate(db=None, service_container=None, event_bus=None)
+    tool = get_tool_registry().get("gate_h_echo")
+    assert tool is not None  # single entry (dict keyed by name — overwrite, not dupe)
+    assert get_step_handler("gate_h_noop") is not None
+    actions = map_query_to_actions("create invoice for Acme")
+    assert len(actions) == 1  # exactly one contributed intent, not two
+
+    # Cleanup so other tests are unaffected
+    await plugin.on_deactivate(db=None, service_container=None, event_bus=None)
+
+
+@pytest.mark.asyncio
+async def test_gate_h_agent_runtime_survives_ai_assistant_absence():
+    """The core tool registry works even though ai_assistant plugin module is never imported."""
+    from app.ai.tool_registry import ToolRegistry, get_tool_registry
+
+    reg = get_tool_registry()
+    assert isinstance(reg, ToolRegistry)
+    # And it must be THE same singleton the shim exposes
+    from app.plugins.builtins.ai_assistant.tool_registry import get_tool_registry as shim_get
+
+    assert shim_get() is reg